add notifications

src/widgets/notification.cpp

@@ -0,0 +1,34 @@
+#include "widgets/notification.hpp"
+
+#include "gtk4-layer-shell.h"
+
+NotificationWidget::NotificationWidget(std::shared_ptr<Gdk::Monitor> monitor, const Glib::ustring &title, const Glib::ustring &message) {
+    if (!monitor) return;
+
+    auto win = new Gtk::Window();
+    win->set_title(title);
+    win->set_default_size(300, 100);
+
+    auto label = Gtk::make_managed<Gtk::Label>(message);
+    label->set_use_markup(true);
+    win->set_child(*label);
+
+    gtk_layer_init_for_window(win->gobj());
+    gtk_layer_set_monitor(win->gobj(), monitor->gobj());
+    gtk_layer_set_layer(win->gobj(), GTK_LAYER_SHELL_LAYER_OVERLAY);
+    gtk_layer_set_anchor(win->gobj(), GTK_LAYER_SHELL_EDGE_TOP, TRUE);
+    gtk_layer_set_anchor(win->gobj(), GTK_LAYER_SHELL_EDGE_RIGHT, TRUE);
+    gtk_layer_set_margin(win->gobj(), GTK_LAYER_SHELL_EDGE_TOP, 2);
+
+    win->add_css_class("notification-popup");
+
+    win->show();
+
+    // Auto close after 3 seconds for demo purposes
+    Glib::signal_timeout().connect([win]() {
+        win->close();
+        delete win;
+        return false; // Don't repeat
+    },
+                                   3000);
+}